The tasks to utilize this contract are to analyze samples from the Calcium for Preeclampsia Prevention trial (CPEP) to measure total 25(0H)D, its isoforms (25(0H)D2 and 25(0H)D3), Vitamin D binding protein (VDBP), albumin, and total calcium in up to 992 serum samples from the CPEP trial. Period of performance for this task is estimated to be 6 months. The purpose of this Task Order is to investigate the Maternal Vitamin D Status and Measures of Neonatal Bone Mineral Content/Density, Body Fat, and Birth Weight in CPEP.